After the PSN/Qriosity hacks, the US House of Representatives asked Sony to answer a few questions. The company wouldn’t send someone in person, but today it did release a letter from Chairman Kazuo Hirai regarding the situation. The letter explained a few things we knew already, and details a file planted in the system.

According to the letter Sony found a planted file in the servers that were attacked. The file was called “Anonymous” and said “We are Legion.” AnonOps has previously denied the attacks on Sony’s PSN. Of course, anyone can easily put that file in there, but it does give some support to the belief that someone in Anonymous was behind the hacks.

The letter sent to Congress also details some timing of the attack. It seems that Sony and the forensics team it had working on the attacks found out that personal data was taken on April 25. The announcement came a day later, on April 26. Sony still holds by the fact that credit card numbers weren’t compromised. The company says it hasn’t seen any reports from credit card companies that there have been fraudulent charges on cards as a direct result of the hackings.

Sony continues to reiterate the measures it’s taking to prevent future attacks, and claims that countries and companies need to join together to prevent something like this happening again. Perhaps others will listen, for consumers let’s hope they do.